In my experience (been using them for a few years now), the difference is that if you contact them (via phone, e-mail or IRC) then they are significantly more l

In my experience (been using them for a few years now), the difference is that if you contact them (via phone, e-mail or IRC) then they are significantly more likely to provide useful support vs. "Hmm, I don't see a problem. Have you tried turning it off and on again?" They are still beholden to Openreach, but they will actively manage them vs. just take them at face value/accept what they are being told.